The Water Guardian is a boss in Silent Hill: Book of Memories. The player will encounter this boss after completing Zone 12.
The reward for beating the Water Guardian boss is the Water Sword.
The Water Guardian is a large blue amphibious monster with four arms and an extended abdomen.
The Water Guardian's lair is a large pool with pipes surrounding the edge of it. For the first half of the battle, the monster only attacks by making its giant hands appear out of the pipes or pool to smash the player. It appears that the monster can combine with the water and summon itself or its limbs anywhere in or around the pool. When the monster emerges, it attempts to suck the player into its mouth or launch a wave at them; both of which can be avoided by keeping distance between the player and the monster.
The Water Guardian symbolizes the subconscious resolution of Trent Baker/Ashley Baker. Their battle is a metaphorical one; symbolizing the struggle between the player's will and Trent's/Ashley's, both attempting to assert their dominance over the other in order to change reality.